In order to keep the time periods for inspection of thermal apparatus and particularly a steam turbine to a minimum, i.e., to ensure brief shutdown times for a plant, it becomes necessary to design individual parts especially housing parts of the turbines in such manner that they will specifically facilitate any servicing. Heretofore, mounting platforms or cover grills were used for inspection and repairs of the turbine at the plant location and assembled in accordance with the structural conditions at the working site or of the plant. In different cases an access plate or grill was supplied by the manufacturer to be utilized when needed, that is for the original assembly or inspection after the removal of the outer turbine housing. Such mounting platforms had again to be removed from the turbine upon the completion of the inspection or repair.